The present invention relates generally to relatively heavy power equipment and more specifically to a vehicular power shovel or shovel loader which is wheel-mounted or crawler-mounted and which includes a lift arm carrying the loading shovel member. The invention relates to the type of device wherein the lift arm is raised and lowered by one or more hydraulically operated cylinders.
In mobile power equipment such as shovel loaders which may include lifting cylinders to operate the device, the location of the lifting cylinders may or may not be of importance. In mobile loaders which operate in locations where their mobility is not limited, it is generally not important how the lifting cylinder is arranged on the shovel loader. The lifting cylinders may be arranged so that good transmission of power to lift arms or other similar devices may be insured. In such cases, the lifting cylinders may be arranged either horizontally or almost vertically and they may act either immediately at the lift arm of the vehicle or at webs, plates or similar elements of the lift arm by means of levers which are mounted on a traverse or the like, with the lift arms being supported at the vehicle frame by means of such a traverse. In this connection, reference is made to prior art such as, for example, German patents No. 12 56 585, 12 39 240, and 11 08 140.
When lifting cylinders are arranged horizontally as seen in the axial direction, and are located behind the lift arm webs, the length of the shovel loader will be increased. When the lifting cylinders are located laterally alongside the lift arm web of the apparatus, the width of the vehicle may be significantly expanded. When lifting cylinders are located below or above the lift arm webs, the loading vehicle tends to have its height increased. Accordingly, overall length, width and height of apparatus such as a shovel loader inevitably resulting from the arrangement of the lifting cylinders can be a significant factor and give rise to important disadvantages in the use of the device where the space within which the device may be used is limited. For example, such limitations may become significant when using apparatus in subsurface mining.
In vehicles of the type described, the overall frame of the vehicle may be swivelled somewhere intermediate the front and rear thereof. That is, some shovel loaders include buckling or bending joints whereby the front part of the vehicle frame may be swivelled or pivoted relative to the rear part of the vehicle frame through a joint or connection, with the swivelling action being effected by hydraulic cylinders or the like.
In such vehicles, the arrangement of the overall actuating device utilized for moving the lift arm must usually be contained within a minimum space in the region of the front portion of the vehicle. That is, considering the vehicle from the point of view of the operating direction thereof, it may be required that the entire actuating mechanism be maintained within the region of the front driving and bearing or carrying axle. In this connection reference is made to U.S. Pat. No. 3,844,370.
In other prior art devices it is also known to connect vertical lifting cylinders with the lift arms of the device through toggle lever gearing so that the lift arm is lifted through traction force (see British Pat. No. 770,866). However, in such a device, the overall height and width of the apparatus cannot be reduced since the lifting cylinder is located laterally above the lift arms.
Thus, it is the intent of the present invention to provide a structure and arrangement for a shovel loader which will tend to advantageously minimize the dimensions of the apparatus and which will not unduly complicate the structure or increase the cost of manufacture.